Fin winding machine



Oct; 10 1933.3 5 W D 1,930,161

FIN WINDING MACHINE Filed June 19, 1928 6 Sheets-Sheet l INVENTOR 1933- E. A. DEWALD 1,930,161

FIN WINDING MACHINE Filed June 19, 1928 6 Sheets-Sheet 2 m R Edward 4 flen a/d vf/s ATTORNEYS Oct. 10,1933. E. A. DEWALD 1,930,161

FIN WINDING MACHINE Filed June 19, 1928 6 Sheets-Sheet 3 INVENTOR Edward A fle/m/d Oct. 10,1933. E. A. DEWALD FIN WINDING MACHINE Filed June 19, 1928 6 Sheets-Sheet 4 &

INVENTOR Fain 0rd A flen a/a.

BY 4., am; w

Ff/ ATTORNEYS Oct. 10,1933. E A DEWALD 7 1,930,161

FIN WINDING MACHINE Filed June 19, 1928 6 Sheets-Sheet 5 LEAD ROLL GROOVIHG ROLL CRIMPING 5'5 INVENTOR 46 ROLL Edward 'Aflerm/d b BY 'f/s ATTORNEYS Patented Oct. 10, 1933 PA'lENT OFFICE FIN WINDING MACHINE Edward A. Dewald, Massillon, Ohio, assignor to The Griscom-Russell Company, New York, N. Y., a corporation of Delaware Application June 19, 1928. Serial No. 286,638

32 Claims.

The subject of this invention is a machine for putting heat-radiating fins on metal tubes, and the object of the invention is to provide a machine for the'rapid and economical manufacture of heat exchange tubes having heat-radiating fins firmly attached thereto without the use of soldered or brazed joints.

The machine illustrated in the accompanying drawings and described and claimed hereinafter represents a preferred embodiment of the invention.

With reference to the accompanying drawings:

Fig. 1 is a view, partly external, and partly sectional of a short length of tubing to which a helical metal fin has been applied in the manner herein described;

Figs. 2, 3, 4, 3a and 4a are enlarged fragmentary longitudinal sectional views illustrating different steps in the process of applying the fin to the tube;

Fig. 5 is an elevational view of the assembled fin applying machine;

Fig. 6 is a plan view of the assembled machine;

Fig. 7 is a longitudinal sectional view taken along the line 7-7 of Fig. 6. This view depicts in section the rotating spindle, the rotating head, the driving clutch, the collet chuck by which the metal tube is held against rotation during the operation of the machine, and other details;

Fig. 7a is a detail of one of the chuck jaws and of the tubular jaw holder through which-the operation of the jaws is controlled;

Fig. 8 is an elevational view of the rotating head taken along the line 8-8 of Fig. 5. This view illustrates, in particular, the relative positions of the grooving roll, lead roll and crimping roll which operate upon the metal tube simultaneously;

Fig. 9 is a cross sectional view through the rotating head taken along the line 9-9 of Fig. 8;

Fig. 10 is a fragmentary cross sectional view through a portion of the rotating head and is taken along the line 10-10 of Fig. 8. This view illustrates in detail the lead roll which functions to guide the metal ribbon into the groove on the metal tube and also the guide block whereby the proper amount of tension is applied to the metal ribbon as it approaches the lead roll;

Fig. 11 is an enlarged sectional view along the line 11-11 of Fig. 8 and shows, in particular, the grooving roll and its adjustable support;

Fig. 12 is an enlarged sectional view taken along theline 12-12 of Fig. 8 and shows, in particular, the crimping roll by means of which the groove in the metal tube is closed after the metal ribbon has been inserted therein;

Fig. 13 is a detailed elevational view of the cam blocks forming part of the rotating head;

Fig. 14 is a longitudinal section along the line 14-44 showing the details of construction of the reel which supports and pays out the metal ribbon;

Fig. 15 is a sectional view taken along the line 15-15 of Fig. 14; 7

Fig. 16 is a detailed-view in cross section illustrating the construction of the reel;

Fig. 17 is a fragmentary sectional view along the line 17-17 of Fig. 14 illustrating the ratchet mechanism for driving the reel;

Fig. 18 is a cross sectional view through the ratchet toothed ring forming part of the reel; and

Fig. 19 is a somewhat enlarged longitudinal section taken on line 19-19 of Fig. 14 showing in detail the principal parts of the tube puller.

The product of this machine is a metal tube, usually copper, having on its exterior a helical fin of metal ribbon, also usually copper, the function of which is to accelerate the transfer of .heat either from the tube to the exterior medium or vice versa depending upon the particular apparatus in which the tube is used. There are many kinds of apparatus in which such tubes are employed, as for example, steam condensers, feed water heaters, liquid and gas coolers, etc. A short length of such a tube is shown in Fig. 1 wherein the metal tube, per se, is indicated by numeral 1 and wherein 2 is the helical metal fin which consists of a ribbon of copper or other metal-having enough ductility to 90 permit of its being bent edgewise without breakmg. g I It is highly desirable in a heat exchanging tube of this sort that the heat radiating fin make a very intimate connection with the tube itself along the entireline of contact in order that the transfer of heat from the tube to the fin may not be obstructed by reason of poor or insuflicient interconnection. Furthermore, it is quite es-. sential that there be a good mechanical joint between the tube and the fin because otherwise the fin would be apt to disengage itself from the tube at the ends of the helix which, of course, would be manifestly objectionable.

In so far as it has been possible to ascertain, the common practice heretofore has been to solder or braze the fin to the tube. In many cases soldering is impracticable because it is not capable of withstanding the temperature to which the tube is to be subjected and furthermore does not make a particularly strong joint. Brazing, of course, is not usually objectionable on that score but it is quite an expensive operation and one which is difficult to carry out, particularly with tubes of small diameter or of very thin material. The tube which is the product of this machine consists of a previously formed tube having a helical heat-radiating fin mechanically attached to its surface, the edge of the fin being literally buried in the metal of the tube. The steps in the manufacture carried out by this machine are shown in Figs. 2, 3, 4 and 4a. As shown in Fig. 2, a groove is first formed in the tube. This is a helical groove which is rolled into the tube on its exterior surface. It will be noted that the metal of the tube is pushed inwardly, as indicated at 4, and this feature in itself has been found to have a particular advantage in that it gives the interior of a thin walled tube a sort of corrugated surface which is effective to agitate the liquid or gas flowing through the tube thus accelerating the transfer of heat from the liquid or gas to the wall of the tube and thence to the fins from which it is radiated, or vice versa. Where a heavy walled tube is employed the operation of forming the helical groove in the exterior surface of the tube does not result in the formation of a corresponding raised portion on the inside of the tube. Accordingly, by using a heavy walled tube it is possible to provide a finned tube having a smooth inner surface.

In Fig. 3 the second step in the operation is illustrated. Here one edge of the metal ribbon 2 forming the fin is shown inserted in the groove 3 and as indicated at 2 the edge of the metal is upset as a result of the pressure with which the ribbon is inserted into the groove. This results in forming a thickened base at 2 which materially assists in anchoring the fin to the tube. The next and final operation is illustrated in Fig. 4. This step consists in compressing the metal of the tube adjacent the groove so as to close the groove into gripping engagement with the fin. The fin is thus locked into the groove and very firmly secured. The operation of compressing the metal of the tube to close the same into gripping engagement with the fin serves to compress the metal of the fin at the outer edge of the groove and accordingly the fin is locked to the tube regardless of whether the root of the fin is expanded by virtue of the pressure applied to the fin when it is inserted in the groove.

The machine herein described forms the groove 3 by the process of rolling, winds on the metal ribbon 2 inserting it in the groove as shown in Fig. 3 while at the same time supporting the ribbon, thereby preventing its buckling during the winding operation, and then closes the groove as illustrated in Fig. 4 or 4a which shows a modified form of lock obtained by a slight adjustment as will be later described. This is all accomplished as a continuous manufacturing process.

In the elevational and plan views of the fin winding machine, Figs. 5 and 6, respectively, a metal tube on which several turns of ribbon form ing the fin have been wound is shown at 5.

Referring for the present to Figs. 5 and 6, the machine illustrated comprises supporting standards 6, 7, 8, 9 and 10 and a base-plate 11 all of which may be made of cast iron. Journaled in the supporting members 7 and 8 is a rotatable hollow spindle 12 (see Fig. '7 one end of which is enlarged in the form of a flange, as indicated at 12. The flange l2 and the parts mounted upon it will be referred to in general as the rotating head. The metal tube on which the fin is to be wound and secured is passed lengthwise through the hollow spindle and rotating head.

The thin ribbon of copper or other ductile metal which is to form the fin is mounted on a reel which is designated as a whole by reference numeral 13. This reel is arranged to be rotated, by means of a gear drive, at the same speed as the spindle 12 and rotating head 12'. The metal tube does not rotate but is held rigidly stationary except for lengthwise travel at. a predetermined rate which determines the pitch of the helical metal fin. The lengthwise movement of the tube is effected by means of a chain 14 which moves continuously at a definite rate during the operation of the machine. The linear movement of this chain is transmitted to the metal tube through the medium of a connecting link in the form of a rod' 15 (see Figs. 14 and 19) provided with suitable jaws for gripping the end of the tube. This device will be referred to as the tube puller.

The reel 13 is driven from the spindle 12 through a train of gears 16, 17, 18 and 19, gears 17 and 18 being keyed to the countershaft 20 to which is also attached a worm-gear 21 driving a worm-wheel 22 which is. connected through a train of gears including the idler 23 to drive the shaft 24 on which is mounted'a sprocket 25 which is the driving sprocket for the chain 14. The other sprocket for this chain is indicated at 26. Adjusting sprocket 27 functions to take up the slack in the chain 14.

Obviously, the relative linear speed of the chain 14 with respect to the speed of rotation of the spindle 12 and rotating head 12 determines the pitch of the metal fin. The pitch of the fin may be regulated by changing the gear ratio between the worm-wheel 22 and the sprocket 25. In this particular instance the machine is so designed that the idler gear 23 is removable and its center adjustable so as to provide for different gear combinations.

The machine is provided with an electric driving motor 28 having on its shaft a driving pinion 29 meshing with a gear 30 which is an integral part of the driving member of a friction clutch (see Fig. 7) through which the machine is driven. The driving clutch member 30 is provided with a bushing 31 which normally runs freely on the hollow spindle 12. The spindle 12 is journaled in the bushing 32 in the supporting standard 7 and in the bushing 33 of the supporting standard 8. The driven member 34 of the clutch is keyed to the spindle 12. A clutch operating sleeve 35 of the usual form is slidably mounted on the spindle 12 and when moved to the left by its operating lever, as viewed in Figs. 5, 6 and '7, causes the clutch to engage thus setting the spindle 12 into rotation. In turn, the rotating head 12' and the reel 13 are set into rotation. Also the chain 14 is set into motion at the predetermined relative speed.

In Fig. 7 the metal tube which is to be operated upon is indicated by reference numeral 1. It is essential that this tube be held quite rigidly at or near the point where the metal ribbon is applied while at the same time the tube must be permitted to move lengthwise smoothly and uniformly. To accomplish this purpose a collet chuck capable of grippingly engaging the metal tube while at the same time permitting smooth lengthwise movement thereof is provided. The collet chuck is illustrated in Figs. 7, 7a and 9. It comprises a pair of diametrically opposed hardened steel jaws 36, the function of which is to grip themetal tube with suificient pressure to hold it against rotation and restrain, but not prevent, its lengthwise movement. In addition the jaws 36 function as sizing dies. Inasmuch as there is some variation in the outside diameter of the tubes as received from the manufacturer it is necessary that the jaws 36 be designed to grippingly engage tubes of the smallest diameter within the allowed range of tolerance for the particular size of tube for which the jaws are designed. Accordingly, the jaws 36 functioning as sizing dies will reduce the diameter of any tube having an outside diameter greater than the minimum. The jaws 36 are slightly tapered externally and are supported within an annular member 37 the bore of which is correspondingly tapered. The taper, of course, functions as in any collet chuck to cause the jaws to grip the tube.

As is shown most clearly in Fig. 7a., the jaws 36 are secured to a tubular member 38 by means of T connections, as indicated at 36 and 28. The tubular member 37 functions to move the jaws 36 longitudinally so as to grippingly engage and disengage the tube 1. Tubular member 38 extends through to the left hand end of the machine, as viewed in Figs. 5 and 6, and is provided with a suitable thread at that end which cooperates with a similarly threaded hand wheel 39 which, when rotated, transmits a longitudinal movement to the tubular member 38 and jaws 36.

It follows then, that the operation of the collet chuck is controlled entirely by the hand wheel 39. The collet chuck comprising jaws 36 and annular member 37 does not rotate but is centered within and supported at one end by the spindle 12 through the medium of a ball bearing 40 by virtue of which the chuck is supported by the rotating spindle without itself rotating. Another tubular member 41 is secured at one end to the annulan member 37 and at the other end is threaded into a large nut 42 which is secured to the support '7. The tubular member 41 holds the chuck member 37 both against rotation and lengthwise displacement. The ball bearings 43 and 44 are thrust bearings for the spindle 12.

Having described the manner in which the metal tube is securely gripped and held against rotation while being permitted to movelengthwise at the proper rate the means and method of grooving the tube and applying the metal fin will now be described.

The metal ribbon which may, for example, be of soft copper and, let us say, inch wide by 3% inch thick (these figures being in no way limiting) is fed from the rotating reel 13 to the rotating head 12, as indicated at 45 in Fig. 5. The three operations to be considered comprise: (l) grooving the tube; (2) bending the ribbon and pressing it into the groove; and (3) closing the groove in the tube into gripping engagement with the ribbon. These operations are performed by tools which are mounted on and rotatable with the rotating head 12. These are illustrated in some detail in Figs. 10, 11 and 12 and shown in their assembled relation in Figs. 8 and 9. The grooving operation is best illustrated in Fig. 11. This is accomplished by means of a grooving roll 46 which is made of hardened tool steel and has a peripheral projection 46' of the desired cross sectional configuration to form the groove. The axis of the grooving roll 46 is preferably set at a slight angle with respect to the axis of the metal tube because of the angular travel of the groovethe groove being a helix. Inasmuch as the pitch of the groove is a variable factor, the angle at which the axis of the grooving wheel is set is preferably determined by the average pitch. That is to say, if the machine is designed for a range of pitch variation between 6 turns per inch and 12 turns per inch the average would be 9 turns per inch. Within reasonable limits it is not material that the tracking angle of the grooving roll does not correspond with the angle of the groove. But, obviously, there is a practical limit to the permissible variation in this respect. As the metal ribbon approaches the tube it is engaged by a rotating wheel 47 known as the lead roll. This has a narrow peripheral groove 47' just wide enough to receive the ribbon edgewise and of the proper depth so that one edge of the ribbon is pressed to the bottom of the groove, as shown in Fig. 3. The function of the lead roll is not only to press the ribbon into the groove but to prevent it from buckling while that operation is being performed. The edgewise bending of the ribbon takes place at the lead roll. Inasmuch as the groove 47 fits the ribbon snugly there is no opportunity for the ribbon to buckle and the only thing it can do is to stretch at the outer edge and compress at the lower edge.

The next operation is that of closing the groove as illustrated in Fig. 4. This operation is most clearly illustrated in Fig. 12 and is accomplished by means of a wheel 48 which is known as a crimping roll. The crimping roll is in appearance very similar to the lead roll 47 in that it has a groove similar to the groove 47' but its function is quite different. The crimping roll has two peripheral edges 48a and 48b which are knurled. The crimping roll being made of hardened tool steel the knurled edges are pressed into the soft metal of the tube causing the groove to close. The knurling on the edges 48a and 48b while notalways strictly essential is highly desirable in that it cuts the surface of the tube adjacent the groove (see Fig. 12) materially facilitating the closing up operation and requiring less pressure than would otherwise be needed.

Fig. 8, which is a front view of the rotating head taken along the line 8-8 of Fig. 5, shows the relative positions of the grooving roll, lead roll and crimping roll, with respect to the metal tube upon which they are operating. The grooving and crimping rolls 46 and 48, respectively, are supported on a mounting plate 49 while the lead roll 47 is supported on another mounting plate 50.

As viewed in Fig. 8 the mounting plates 49 and 50 are divided along the irregular line 51-the line of division passing between the lead roll on one side and the grooving and crimping rolls on the other side. These two plates are slidably adjustable toward and away from each other by means of adjusting screws 52 and 53. The reason for making the mounting plates 49 and 50 adjustable is to provide for initial adjustments of the three rolls with respect to the tube. It is apparent that the grooving roll, lead roll and crimping roll must be initially adjusted each to a particular position with respect to the center line of the tubing, as viewed in Fig. 8, in order that each may perform its function correctly. These adjustments are accomplished, in part, by moving the mounting plates 49 and 50 by means of the adjusting screws 52 and 53. Each of the 150 mounting plates 49 and 50 has three clamping screws 54 which are loosened preliminary to making the aforementioned adjustments and are tightened when the adjustments are completed. The mounting plates 49 and 50 are mounted, respectively, on members 55 and 56 which, for convenience of terminology, will be called cam blocks because they are formed with integral cam surfaces at 55' and 56, respectively. The cam blocks 55 and 56 are also mounted to be slidable toward and away from each other in the same directions as the mounting plates 49 and 50. A front view of the cam blocks 55 and 56 is shown in Fig. 13. This view is taken as observed from the same point as Fig. 8 but with the mounting plates 49 and 50 and other obscuring parts omitted.

A pair of helical springs seated, respectively, in the recesses 57 and 58 (see Fig. 13) tend to yieldably separate the cam blocks 55 and 56, but during the operation of the machine the action of these springs is opposed by cams 59 and 60 which are carried by the annular member 61. It will be noted that the faces of the cams 59 and 60 conform to the curvature of the cam surfaces 55 and 56', and it will be observed that when the annular member 61 is rotated in a counter-clockwise direction, as viewed in Fig. 8, the action of the cams will result in sliding the cam blocks toward each other in opposition to the separating force exerted by the springs in recesses 57 and 58.

The limit of movement in this respect is reached when the two cam blocks meet as shown in Fig. 13. The reason for the provision of cam blocks 55 and 56 and the operating cams 59 and 60 is to make it possible quickly to enlarge the opening between the rolls 46, 47, 48 carried by the mounting plates so as to permit the insertion therebetween of a successive length of tubing. The annular member 61 is rotatable relatively to the flanged head 12' of the spindle 12. A circular member 62 having a central opening is bolted to the flange 12 and is arranged as shown in Fig. 9 to secure the annular member 61 in place while permitting the latter to rotate. The cam blocks 55 and 56 are slidably mounted on the circular member 62 by means of a dovetail slide, as shown in Fig. 7. The peripheral surface of the annular member 61 is preferably knurled, as shown in Fig. 5, so that it may be more easily operated by hand, and it should also be provided with spanner holes or some suitable provision made whereby a bar may be attached to it for tightening and loosening.

As shown in Figs. 8 and 11, the grooving roll 46 is adjustable toward and away from the center of rotation of the spindle independently of the adjustability of the mounting plate 49. This is accomplished by mounting the grooving roll on a slidably adjustable supporting bracket 63 which is secured to the mounting plate 49 by means of a clamping screw 64. Adjustments are accomplished by means of the adjusting screw 65.

A feature of considerable importance which it is well to note at this point is that the grooving roll, lead roll and crimping roll form a three-point support for the tube-the lateral pressure exerted by each roll against the tube being opposed by the other two rolls and there is, accordingly, little or no residual lateral pressure against the end of the tube to which the tube puller is attached. Consequently, no additional support for the tube is needed.

A ribbon guide block 66, shown in Figs. 8 and 10, has a long rectangular aperture 67 through which the metal ribbon 2 passes on its way to the lead roll 47. The aperture 67 is preferably designed to be just large enough to allow the metal ribbon to run through it freely. A set screw 68 (see Fig. 10) is arranged to make frictional contact with the ribbon 2 as it passes through the aperture 67. This set screw is intended to be adjusted to put proper tension on the ribbon so that it will be adequately taut as it approaches the lead roll and the metal tube. Without this tension the ribbon would not be properly seated in the groove and could not be satisfactorily secured therein by the crimping roll.

In preparing for operation, a piece of tubing of the size to be operated upon is gripped in the chuck with the mounting plates 49 and 50 and the cam blocks 55 and 56 opened up. Assuming that the initial adjustment of the rolls will permit, the cam blocks are closed together by means of the annular member 61 and then the mounting blocks are adjusted until the lead roll and the crimping roll are in the correct or approximately correct positions to perform their respective functions. The grooving roll is then adjusted until the groove which it produces is of the desired depth. When the settings of the three rolls are satisfactory and the clamping screws 54 and 64 are tightened, the machine is ready for continuous operation on the particular size of tubing for which it has been adjusted. By changing the chuck jaws and readjusting the rolls tubing of different sizes may be operated upon.

The ribbon reel illustrated in Figs. 14 to 18, inclusive, will now be described. The coil of copper or other metal ribbon occupies the space 69 (see Fig. 14) and is supported by four wedge blocks 70 disposed at 90 about the center of the reel (see Figs. 15 and 16). The wedge blocks 70 are adjustable radially by means 1 of complementary wedge blocks 71 which are threaded to receive a large internally threadedring 72 by means of which the wedge blocks 70 and71 are caused to slide relatively along their inclined surfaces whereby wedge blocks 70 are moved outward radially to grip the inside of the coil of metal ribbon. This is to prevent the coil of ribbon from slipping around on the reel and consequently unwinding too fast. At the sides of the reel are two circular steel discs '73 and 74, respectively, the former of which is removable for the purpose of putting the coil of ribbon in place, while the latter carries a guide roller which directs the ribbon as it is drawn off the reel to the rotating head 12' which carries the fin applying devices. The gear 19 drives the reel and is rotatably mounted on a sleeve '75 which in turn is secured to a bracket 76 attached to the frame of the machine. The sleeve 75 supports both the gear and the reel.

The steel disc 74 is bolted to the gear 19 and is positively driven at the same speed as the rotating head. The hub of the gear 19 is extended to form a bearing on which is mounted a sleeve '77. The sleeve '77 is rotatable on the hub of the gear 19. This sleeve has four slots as shown in Figs. 15 and 16 in which the wedge blocks '70 and '71 are seated. Since the metal ribbon must be fed from the reel as the operation of the machine proceeds it is obvious that the latter must be permitted to overrun the gear 19 and the disc 74. For this purpose a ratchet and pawl connection is provided between the gear 19 and the sleeve 77. This comprises a ratchet toothed ring '78 (Fig. 18) which is secured to the sleeve '17, and a pair of spring pressed driving pawls 79 carried by gear 19, details of which are shown in Fig. 17. The ratchet and pawl connection precludes any possibility of the reel lagging behind the gear 19 while at the same time it permits the latter to rotate relatively to the gear 19 and in the same direction of rotation.

' It is desirable that the metal ribbon, as it is being payed out from the reel, be kept fairly taut and in order to do this means are provided for frictionally impeding the reel against rotation relatively to gear 19. For this purpose an externally threaded ring is secured to one end of the sleeve 75 and a large nut 81 is screwed on to that ring. One edge of the large nut 81 has a groove in which is seated a ring of steel balls 82 which bear against a hardened steel ring 83 which is fastened to the sleeve 77 and rotatable therewith. By turning the nut 81 the balls 82 may be brought to bear against the ring 83 with a varying degree of pressure and in turn the sleeve 77 is caused to bear against the disc 74 with equal pressure. Consequently the sleeve 77 may be frictionally restrained to the desired extent by adjusting the position of the nut 81. When this nut has been regulated to provide the desired amount of restraint on the sleeve the stop screws 84 which are carried by the nut 81 may be set and locked.

From the guide roller 85 the metal ribbon passes to a similar roller supported on a bracket attached to the rotating head 12'. Inasmuch as the rotating head and the disc '74 rotate at the same speed the pulleys 85 and 86 are always opposite each other.

The construction of the tube puller will now be described with reference to Figs. 14 and 19. This device comprises a steel rod 15 having attached to it at one end portion a pair of spaced collars 87, 88 between which, and slidably mounted on the rod, is a connector 89 which is designed to engage the chain 14 as shown in Fig. 14. The object of making the connector 89 slidable along the rod 15 is to give it sufiicient play so that it will be able to engage one or the other of two successive links of the chain. To the other end of the rod 15 there is attached a tube gripping device. This comprises a collet 90 and a cooperating sleeve 91. externally while the sleeve 91 is correspondingly tapered internally. The collet is slotted and preferably spring tempered and has a series of teeth 92 which are adapted to grippingly engage the tube 1 when the collet is contracted as the result of opposing forces applied to the collet and the sleeve. In other words, when tension is applied to the tube puller rod the collet 90 is caused to contract proportionately into gripping engagement with the tube. For the purpose of supporting the end of the tube 1 against the pressure exerted by the teeth 92 a pilot 93 is inserted in the end of the rod 15. The sleeve 91 is secured to the rod 15 through the medium of a threaded bushing 94 and a nut 95 which is threaded on to the rod. In Fig. 14 there is shown mounted on the rod 15 a steel sleeve 96 which is slidable along the rod 15. The sleeve 96 has been omitted from the showing of Fig. 19 because of lack of space. The sleeve 96 is knurled externally and its function is that of a releasing device to be used by the operator of the machine for releasing the hold of the gripping device on the end of the tube. Due to the rather acute angle of the taper of the collet 90 and that of the sleeve 91 the tube gripping device is apt to resist releasing in which event the operator uses the steel sleeve 96 as a hammer to strike the end of the sleeve 91. This will relieve the gripping engagement between the sleeve 91 and the collet 90 and permit the collet to expand thus releasing the tube.

The collet 90 is tapered To apply the fin to a heat exchanger tube the operator inserts the tube through the spindle of the machine gripping it in the chuck by means of the hand wheel 39 with one end projecting through the rotating head to whatever extent may be desired but sumciently at least to permit the tube to be engaged by the tube puller in the mannerdescribed. The annular member 61 is then rotated by the operator for the purpose of closing the cam blocks and bringing the grooving roll, lead roll and crimping roll into position to perform their respective operations on the tube. With the tube puller attached and connected to the chain 14 the machine is started temporarily by engagement of the driving clutch. The formation of the helical groove in the tube is thus begun. The metal ribbon having been inserted through the aperture 67 in the tension block 68 and through the grooves in the lead roll and crimping roll respectively the operator winds the end of the metal ribbon around the tube by hand, making two or three turns, and holds one end of it while he again starts the machine. This permits the lead roll and crimping roll to get into action and as soon as a short length of the ribbon has been properly anchored in the groove the operator may release his hold on the end of the ribbon and the machine will proceed to perform the operation of attaching the fin. When the fin has been applied to the tube to the desired length the machine is stopped by the operator. The annular member 61 is then turned to release the cam blocks thus bringing the rolls out of engagement with the tube and the machine is again started up and allowed to form two or three additional turns of ribbon. These turns are not attached to the tube but are cut off by the operator from the attached fin to form a loop on the end of the ribbon through which the next succeeding tube is passed. This provides a more convenient way of starting the succeeding finning operation since it does not make it necessary for the operator to twist the ribbon around the next and other succeeding tubes. All the operator need do is grip the coil of ribbon with his hand for a moment while the finning operation is being started after "which he can release it.

As explained above, the grooving roll, the lead roll and the crimping roll are adjusted on their respective supports to properly perform their several operations upon the tube. If the lead roll is adjusted so that the fin is maintained perpendicular to the tube and the groove formed by the grooving roller is not materially wider than the thickness of the fin, as shown in Fig. 2, the fin will be anchored in the tube in the manner shown in Fig. 4. If desired, however, a connection between the fin and the tube such as shown In Fig. 4a may be produced by providing a somewhat wider groove in the tube and adjusting the lead roll to a very slight angle with respect to the tube so as to cause the inner edge of the fin to turn to one side when pressed against the bottom of the groove by the lead roll as shown in Fig. 3a. This latter form of connection between the fin and the tube is useful where the metal of the tube is soft.

A machine as herein described capable of operating on tubes up to and including one inch outside diameter has been constructed and successfully operated. The operation is exceedingly rapid as compared with other known methods of applying helical fins and the fins are very firmly secured to the tube.

While the machine herein described is regarded as the preferred embodiment it is apparent that many modifications and deviations from the particular structure described may be made without departing from the spirit and scope of the invention as defined by the appended claims.

What I claim is new and desire to secure by Letters Patent of the United States is:

1. In a machine for winding and securing a metal fin on a metal tube, a chuck operable to engage the tube which is to be operated upon to permit a lengthwise feeding movement of said tube while exerting a restraining force against such movement and against the rotation of the tube, a rotatable member through which said tube is fed lengthwise, a plurality of devices mounted on and rotatable with said member, said devices including a tool for forming a helical external groove in said tube, a device for guiding the metal fin into said groove and a tool for compressing the metal of the tube adjacent the groove in such a way that the groove grippingly engages the fin, and means for feeding said tube lengthwise against the frictional restraining force of the chuck to cause said ribbon to be wound helically upon the tube.

2. In a machine for winding and securing a metal fin on a metal tube, a chuck through which the tube to be operated upon is fed lengthwise, said chuck being operable to contract into gripping engagement with said tube and to expand to release said tube, said chuck when contracted being effective to permit a lengthwise feeding movement of said tube while exerting a restraining force against such movement and against the rotation of the tube, a rotatable member through which said tube is fed lengthwise, a plurality of devices mounted on and rotatable with said member, said devices including a tool for forming a helical external groove in said tube, a device for guiding the metal fin into said groove and a tool for compressing the metal of the tube adjacent the groove in such a way that the groove grippingly engages the fin, and means for feeding said tube lengthwise against the frictional restraining force of the chuck to cause said ribbon to be wound helically upon the tube.

3. In a machine for winding and securing a helical metal fin on a metal tube, a supporting frame, a rotatable hollow spindle journaled in said frame, means for rotatably driving said spindle, a chuck concentrically mounted within said spindle and adapted to permit passage therethrough of a metal tube to be operated upon, means for operating said chuck to grippingly engage said tube to permit a lengthwise feeding movement of said tube while exerting a restraining force against such movement and against the rotation of the tube. a groove forming tool rotatable with said spindle and operable to form an external helical groove in said tube, means rotatable with said spindle for guiding the metal fin and pressing one edge portion thereof into said groove, 9. tool rotatable with said spindle for distorting the metal of said tube adjacent said groove thereby causing said groove to firmly grip said fin, and means operable to pull said tube lengthwise through said chuck and spindle a predetermined distance for each revolution of said spindle to cause said ribbon to be wound helically upon the tube.

4. In a machine of the class described, a rotatable head having an axial opening through which the metal tube to be operated upon is adapted to pass lengthwise, a pair of tool carrying members mounted on said head, said members being separable to permit the insertion of the tube therebetween, spring means tending to separate said members, and a cam device operable to move said members toward each other in opposition to said spring means, a grooving tool carried by one of said members, a lead wheel carried by one of said members, and a compressing tool carried by one of said members.

5. In a machine for winding and securing a helical metal fin on ametal tube, means for imparting a lengthwise feeding movement to said tube at a predetermined relative rate, a grooving roll, a lead roll and a crimping roll between which said tube passes in its lengthwise travel, and means for applying tension to the fin strip as it approaches said lead roll said grooving roll being operable to form a helical exterior groove in said tube, said lead roll being operable to guide the metal fin into said groove and to support the fin against buckling, said crimping roll being operable to close said groove into gripping engagement with the fin.

6. In a machine for winding and securing a helical metal fin on a metal tube, means for imparting a lengthwise feeding movement to the tube at a predetermined relative rate, means for securing the tube against rotation, a plurality of tools arranged to revolve about said tube, said tools including a grooving roll and a crimping roll, said grooving roll being operable to form a helical exterior groove in said tube, said crimping roll being operable to compress the metal of said tube adjacent said groove into gripping engagement with the fin. means for guiding and inserting one edge portion of the metal fin into said groove preceding the operation of said crimping roll, and means for applying a proper tension to said fin while it is being inserted in said groove.

'7. In a machine for winding and securing a helical metal fin on a metal tube, means for supporting the metal tube and restraining it against rotation, means for imparting a lengthwise feeding movement to said tube at a predetermined relative rate. a grooving roll, a lead roll and a crimping roll, all of said rolls being arranged to revolve about said tube, said grooving roll being operable to roll a helical exterior groove into said tube, said lead roll having a peripheral groove of suitable proportions to permit the metal ribbon which is to form the fin to pass therethrough while at the same time supporting said metal ribbon against buckling, said lead roll being operable to press one edge portion of the metal ribbon into the groove formed by said grooving roll, said crimping roll being operable to compress the metal of said tube adjacent said groove so as to cause said groove to close up into gripping engagement with the metal ribbon seated therein, and means for applying tension to said ribbon as it approaches said lead roll.

8. In a machine for winding and securing a helical metal fin on a metal tube, a chuck operable to grip the metal tube and hold it against rotation while permitting said tube to be moved lengthwise, a spindle, a rotatable head driven by said spindle, said chuck, spindle and rotating head being coaxial, said rotating head comprising a pair of mounting plates and a pair of cam blocks, each of said mounting plates being mounted on one of said cam blocks respectively, said cam blocks together with their respective mounting plates being slidable toward and away from each other and toward and away from the axis of said rotating head, spring actuating means tending to force said cam blocks apart, and

means comprising cams operable to force said cam blocks toward each other, a grooving roll, a crimping roll and a lead roll, each of said rolls being carried by one of said mounting plates, said rolls being arranged to revolve about the axis of said rotating head and adapted to be moved in a direction away from said axis in response to separation of said cam blocks and to move into engagement with said metal tube when said ca'm blocks are forced together, said grooving roll being operable to form a helical groove in said tube, said lead roll being operable to guide the metal ribbon into said groove and to support the ribbon against buckling, and said crimping roll being operable to compress the metal of said tube adjacent said groove so as to close said groove into gripping engagement with said ribbon.

9. In a machine for winding and securing a helical metal fin on a metal tube, means for holding the metal tube against rotation, means I for feeding said tube lengthwise at a predetermined relative rate, three rolls each angularly displaced from the others about the center of said tube, said rolls being in contact with said tube and forming a three-point support, one of said rolls being a grooving roll and operable to roll a helical groove in said tube, another of said rolls being a lead roll operable to support and insert a metal ribbon edgewise into said groove, the other of said rolls being a crimping roll operable to close said groove into gripping engagement with said ribbon, said rolls being adapted to revolve about the center of said tube.

10. In a machine for winding and securing a helical metal fin on a metal tube, means for holding the metal tube against rotation, means for feeding said tube lengthwise at a predetermined relative rate, three rolls, each angularly displaced from the others about the center of said tube, said rolls being in contact with said tube and forming a three-point support, one of said rolls being a grooving roll and operable to roll a helical groove in said tube, another of said rolls being a lead roll operable to support and insert a metal ribbon edgewise into said groove, the other of said rolls being a crimping roll operable to close said groove into gripping engagement with said ribbon, said rolls being adapted to revolve about the center of said tube, and movable supporting means for said rolls whereby said rolls may be moved into and out of engagement with said tube.

11. In a machine for winding and securing a helical metal fin on a metal tube, a mechanism for pulling the tube lengthwise at a predetermined relative rate, said mechanism comprising a movable chain and a tube puller for interconnecting one end of the tube with said chain, said tube puller comprising a rod, a tube gripping device attached to one end of said rod and a connector attached to the other end of said rod, said connector being movable lengthwise of said rod and adapted to engage said chain.

12. In a machine for winding and securing a helical metal fin on a metal tube, a mechanism for pulling the tube lengthwise at a predetermined relative rate, said mechanism comprising a movable chain and a tube puller for interconnecting one end of the tube with said chain, said tube puller comprising a rod having a tube gripping device attached to one end thereof, said tube gripping device comprising a toothed collet having an external taper and a sleeve having an internal taper for engaging the external taper of said collet, said sleeve being attached to said rod.

13. In a machine for winding and securing a helical metal fin on a metal tube, a mechanism for pulling the tube lengthwise at a predeter-- mined relative rate, said mechanism comprising a movable chain and a tube puller for intercdnnecting one end ofthe tube with said chain, said tube puller comprising a rod having a tube gripping device attached to one end thereof said tube gripping device comprising a toothed collet having an external taper and a sleeve having an internal taper for engaging the external taper of said collet, said sleeve being attached to said rod, and a pilot projecting from the same endof said rod as that to which said tube gripping device is attached, said pilot being adapted to be inserted in, the end of the tube and to support the tube against the biting action of said collet.

14. In a machine for winding and securing a helical metal fin on a metal tubeJ a reel adapted to support a coil of metal ribbbn, a positively driven rotating member, a ratchet and pawl mechanism interconnecting said reel and said member whereby said reel may be rotatably driven by said member and by virtue of which said reel may be rotated relatively to said member in the same direction of rotation.

15. In a machine for winding and securing a helical metal fin on a metal tube, a reel adapted to support a coil of metallribbon, a positively driven rotating member, a ratchet and pawl mechanism interconnecting said reel and said member whereby said reel may be rotatably driven by said member and by virtue of which said reel may be rotated relatively to said member in the same direction of rotation, and frictional retarding means for impeding the rotation of said reel relatively to said member.

16. In a machine for winding and securing a helical metal fin on a metal tube, a rotatable spindle, means operated by said spindle for attaching to a metal tube a metal ribbon in the form of a helical fin, a reel having its axis of rotation substantially coaxial with said spindle, said reel being adapted to support a coil of metal ribbon, means for drivingly interconnecting said reel with said spindle whereby said reel is rotatable at the same speed of rotation and in the same direction of rotation as said spindle, and a ratchet mechanism whereby said reel is rotatable relatively to said spindle in one direction only.

17. In a machine for winding and securing a helical metal fin on a metal tube, a rotatable spindle, a rotatable member substantially coaxial l with said spindle and drivingly interconnected therewith whereby said member rotates at the same speed as said spindle, a ribbon carrying reel coaxial with said member and adapted to be positively rotated in one direction by said member at the same speed as that of said spindle, the means for drivingly interconnecting said reel and said member comprising a ratchet and pawl mechanism whereby said reel may be rotated in one direction relatively to said member, there being frictional engagement between said reel and said member whereby said member frictionally impedes said reel against rotation relatively thereto, and means for regulating and adjusting the frictional impedance of said member upon said reel.

18. The combination with a reel of a coaxial rotatable member adapted to drivingly rotate said reel there being frictional engagement between said reel and said member whereby said member exercises a frictional retarding action on said reel, a ratchet and pawl mechanism interconnecting said reel and said member whereby said reel may be positively driven in one direction by said member and whereby said reel may be rotated in the same direction relatively to said member, the arrangement being such that said reel cannot be rotated at a slower speed than that of said member but can be rotated in one direction at a greater speed than said member.

19. In combination, a gear having an extended hub, means for driving said gear, a reel comprising a sleeve rotatably mounted on said hub and coaxial with said gear, a ratchet and pawl mechanism drivingly interconnecting said sleeve with said gear whereby said sleeve is positively drivable in one direction by said gear, a plurality of sets of wedge blocks carried by said sleeve, said wedge blocks being operable to be moved into gripping engagement with the interior of a coil which may be supported thereon, a nut operable to exert pressure on said sleeve to exert a frictional retarding action thereon whereby to regulate the amount of force required to rotate said reel relatively to said gear.

20. In a machine of the class described, a chuck operable to hold a metal tube against r0- tation while permitting lengthwise movement thereof, a rotatable head comprising means for securing a metal ribbon to said tube in the form of a helical fin, a reel substantially coaxial with said rotatable head, said reel being adapted to hold a coil of metal ribbon and operable to rotate in the same direction and at the same speed as said rotatable head, the ribbon from said reel being supplied to said rotating head for attachment to the metal tube, driving means interconnecting said rotating head with said reel whereby said reel is positively rotated at a speed equal to that of said rotating head, said reel being free, however, to rotate at a speed in excess of that of said rotating head in response to the tension applied to the metal ribbon as it is drawn from said reel.

21. In a machine for winding and securing a metal ribbon edgewise upon a tube, a chuck operable to engage the tube which is to be operated upon to permit a lengthwise feeding movement while exerting a restraining force against such movement and against the rotation of the tube, a groove-forming tool, a ribbon-bending tool, and a metal-displacing tool mounted for rotation about the axis of said tube and acting respectively to form a groove in the tube, to bend said ribbon edgewise into said groove, and to displace the metal of the tube against the ribbon, and means for feeding said tube lengthwise to cause said ribbon to be wound helically upon the tube.

22. In a machine for winding and securing a metal ribbon edgewise upon a tube, a chuck operable to engage the tube which is to be operated upon to permit a lengthwise feeding movement while exerting a restraining force against such movement and against the rotation of the tube, a groove-forming tool, a ribbon-bending tool, and a metal-displacing tool mounted for rotation about the axis of said tube and acting respectively to form a groove in the tube, to bend said ribbon edgewise into said groove, and to displace the metal of the tube against the ribbon, and means having a swivel connection with said tube for feeding the tube lengthwise to cause said ribbon to be wound in helical formation about said tube a metal-displacing tool, said tools acting respectively to form a groove in the tube, to bend the ribbon edgewise into said groove, and to displace the metal of the tube against the ribbon, and means for feeding said tube lengthwise to cause said ribbon to be wound in helical formation upon and secured to the tube.

24. In the manufacture of tubes having a continuous metal ribbon secured edgewise in a helical groove on the outside of the tube, the method of starting the winding operation upon a length of tube which comprises, winding the leading end of the ribbon which is to be wound on the tube edgewise to form a plurality of convolutions having an inside diameter sufficient to permit the tube to be freely inserted therein, initiating the formation of the helical groove in the outside of the tube, placing said edgewise-wound convolutions upon the tube where the formation of said groove has been initiated, and compressing said convolutions against the tube while rotating the one relatively to the other until the edge of said ribbon enters said groove, and maintaining said compression while permitting the said convolutions to rotate with the tube until said winding operation commences.

25. In a machine of the class described, a rotatable head having an axial opening through which the metal tube to be operated upon is adapted to pass lengthwise, a pair of tool carrying members mounted on said head, a grooving tool carried by one of said members, a lead wheel carried by one of said members, and a compress ing tool carried by one of said members, said members being separable to permit the insertion of the tube therebetween.

26. In a machine of the class described, a head having an axial opening to receive the metal tube to be operated upon, a pair of tool carrying members mounted on said head, said members being separable to permit the insertion of the tube therebetween, spring means tending to separate said members, and a cam device operable to move said members toward each other in opposition to said spring means, a grooving tool carried by one of said members, a lead wheel carried by one of said members, and a compressing tool carried by one of said members.

27. In a machine of the class described, a head having an axial opening to receive the metal tube to be operated upon, a pair of tool carrying members mounted on said head, a grooving tool carried by one of said members, a lead wheel carried by one of said members, and a compressing tool carried by one of said members, said members being separable to permit the insertion of the tube therebetween.

28. In a machine for winding and securing a helical metal fin on a metal tube, means for supporting the tube, three rolls each angularly displaced from the others about the center of said tube, said rolls being in contact with said tube and forming a three-point support, one of said rolls being a grooving roll and operable to roll a helical groove in said tube, another of said rolls being a lead roll operable to support and insert a metal ribbon edgewise into said groove, the other of said rolls being a crimping roll opera groove in said tube, a lead roll for supporting and inserting a metal ribbon edgewise into said groove and a crimping roll for closing said groove with the edges thereof in gripping engagement with said ribbon, the said. tool and a; g angularly displaced from each other about said tube to form a three-point support therefor.

30. In a machine for winding and securing a helical metal fin on a metal tube, three rolls each angularly displaced from the others about the center of said tube, said rolls being in contact with said tube and forming a three-point support for the same, one of said rolls being a grooving roll and operable to roll a helical groove in said tube, another of said rolls being a lead roll operable to support and insert a metal ribbon edgewise into said groove, the other of said rolls being a crimping roll operable to close said groove into gripping engagement with said ribbon, and movable supporting means for said rolls whereby the same may be moved into and out of engagement with said tube.

31. In a machine for winding and securing a helical metal fin on a metal tube, a grooving tool for forming a helical groove in said tube, a lead roll operable to support and insert a metal ribbon edgewise into said groove, and a crimping roll for closing said groove so that the edges thereof grip the ribbon, the said tool and rolls being angularly displaced from each other about the tube to a three-point support therefor, and movable supporting means for said tool and rolls whereby the same may be moved into and out of engagement with said tube.

32. In a machine for winding and securing a helical fin on a tube, a tool operable to form a helical groove in the exterior of said tube, means for seating a ribbon edgewise in said groove, comprising a wheel having a peripheral groove through which the ribbon passes to support the ribbon against buckling, an adjustable set screw for frictionally engaging the ribbon to apply tension to the same as it approaches said wheel, and a tool operable to compress the material of said tube adjacent said groove into gripping engagement with said ribbon whereby said ribbon is firmly secured in said groove.

EDWARD A. DEWALD. 

